This portable lamp is just a gallon milk jug filled with water, with a headlamp pointing into it. It's a clever repurposing trick that creates a great soft light perfect for reading, writing or illuminating the outdoors.

Flickr user listorama took this picture of his "reading lamp" inside his Subaru station wagon, and says it works just as well on a picnic table too. The milk jug filled with water cuts down the glare of the headlamp and diffuses the light very nicely.